John Szum is an American open water swimmer
who participates in the annual Nantasket Beach Swim
, a charity swim
organized by Kitty Tetreault
. After losing his wife to cancer, Zsum has raised the most amount of money to support Swim Across America
's program to support cancer research, prevention and treatment through the 1/2-mile and 1-mile swims along the shores of Nantasket Beach in Hull, Massachusetts.